Computation of 'ulimit -dH' hard-limit values?

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

Just how are the hard limit values for 'ulimit' (particularly data size,
"-d") calculated?  Are there any machine-dependencies that affect this
calculation?

What I've observed on i386, amd64 and sparc is that the hard limit is
approximately RAM+swap.

On macppc (other powerpc platforms?) it appears to be:

  min(RAM+swap, 1GB)

I have a macppc system with 1GB real RAM and 1GB swap, yet 'ulimit -dH'
claims 1048576 (KB).

I have another macppc system with 2GB real RAM and 2GB swap and there
'ulimit -dH' also claims 1048576.

Curious.

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